1, 2. Boast,brag imply vocal self-praise or claims to superiority over others. Boast usually refers to a particular ability, possession, etc., that may be one of such kind as to justify a good deal of pride: He boasts of his ability as a singer.Brag, a more colloquial term, usually suggests a more ostentatious and exaggerated boasting but less well-founded: He brags loudly of his marksmanship.

The notion apparently is of being "puffed up" with pride; cf. Old English belgan "to become angry, offend, provoke," belg "anger, arrogance," from the same root as bellows and belly (n.). Related: Boasted; boasting. An Old English word for "boasting" was micelsprecende, "big talk."

v.

early 14c., "to brag, speak arrogantly;" from the same source as boast (n.). Related: Boasted; boasting.